The present invention relates to neonatal development, and more particularly to the development and coordination of sucking, swallowing and breathing abilities. While the neurological and tissue development for these biological activities generally occurs early in fetal development, it is still relatively common for extremely premature or low birth weight infants to enter the world with no suckling reflex, poorly developed breathing ability, and possibly other neurological deficits requiring that they be maintained on various support systems including cardiac, breath and feeding systems for the first weeks of their lives. Under these circumstances, feeding is initially effected by direct nasal intubation to the intestine.
The transition from tube feeding to breast or bottle feeding requires the development of the ability to suck and also to coordinate sucking with swallowing and breathing. Low birthweight neonates as well as newborn cardiac surgery patients making this transition often exhibit feeding apnea during which nasal airflow ceases entirely for a period of several seconds. This apnea may result from excess milk flow, from lack of coordination between swallowing and breathing, or from repeated swallowing. The degree of difficulty in making the transition from tube feeding to bottle feeding may be compounded by the presence of apnea of prematurity, as well as by other factors. These difficulties may necessitate continuous monitoring, prolonging the time interval that the neonate remains in the intensive care or transitional care unit.
Numerous researchers have investigated the development of sensorimotor pathways and developmental factors responsible for activity of the perioral region, and a number of sensing techniques for evaluating or diagnosing deficits of muscular activity or nerve activation in that area have been developed. In addition, a range of practical devices such as pacifiers have been suggested or promoted for enhancing the development or increasing the functional ability of an infant's nursing. However, these generally rely on the presence of a threshold level of sucking competence. Initially, for the above-mentioned classes of infants, such competence is absent, and the transition to bottle or breast feeding is therefore a critical one which can require full-time observation and close attention by a nurse/monitor during feeding.
Sucking behavior is believed to depend both on control of a neuronal network located in the brain stem reticular formation, as well as on afferent feedback of nerve signals from the facial and mouth tissues. Observations on healthy infants have identified several patterns of sucking, and have commonly also noted the infants ability to change the nature or type of sucking activity based on the presence or absence of liquid nutrients. Furthermore, certain natural frequencies of sucking activity closely related to the breathing cycle have also been identified in a range of normal sucking behavior. These observations of a temporal coordination or phase relationship of breathing and sucking suggest the involvement of related neuronal systems. More recently, Finan and Barlow, in J. Speech and Hearing Res. 39:833-839 (August, 1996) have suggested the use of an instrument which they call an actifier, to alter the sucking response by operating as a stimulus within the frequency band of normal sucking movement. The device applies a periodic pressure pulse to the nipple of a pacifier, and measures muscular responses in the mouth of the infant. The actifier of those researchers essentially was used to investigate responsiveness of the sucking neuronal control to cyclic mechanical stimulation of the intraoral tissue in normal full term human infants and neonates. Substantial questions remain as to whether such stimulation would produce similar results in very low birth weight or post operative cardiac neonates, as well as their ability to respond to such stimuli, and whether such stimulation may have any effect on the initial development of, or the mechanisms by which, competence is acquired.
Accordingly, there remains a need for a device for diagnosing or managing or training neonatal sucking and feeding deficits during the transition from feed tube intubation to autonomous feeding.
There is also a need for a device that reduces the degree of individualneed for, or the demands placed upon, a human monitor during the time a neonate makes the transition to natural feeding.